Evaporative cooling: water for thermal comfort

Abstract

Evaporative cooling is an environmentally friendly air conditioning system that operates using induced processes of heat and mass transfer, where water and air are the working fluids. It consists, specifically, in water evaporation, induced by the passage of an air flow, thus decreasing the air temperature. This paper presents three methods that can be used as reference for efficient use of evaporative cooling systems, applying it to several Brazilian cities, characterized by different climates. Initially it presents the basic operation principles of direct and indirect evaporative cooling and defines the effectiveness of the systems. Afterwards, it presents three methods that allows to determinate where the systems are more efficient. It concludes that evaporative cooling systems have a very large potential to propitiate thermal comfort and can still be used as an alternative to conventional systems in regions where the design wet bulb temperature is under 24ºC.